The Effect of Inspiratory Resistance on Exercise Performance and Perception in Moderate Normobaric Hypoxia

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Respiratory Physiology

Background:

• Respirators protect against airborne toxins but may impair physical performance.
• Understanding the impact of inspiratory resistance on exercise is crucial for worker safety and efficiency.

Purpose of the Study:

• To determine the effect of varying inspiratory resistance on physical performance.
• To assess the impact of inspiratory resistance on breathing perception during exercise in normobaric hypoxia.

Main Methods:

• Healthy men performed submaximal and maximal exercise on a cycle ergometer under normobaric hypoxia (17% O2).
• Participants used a respiratory mask with four inspiratory resistors (0, 1.5, 4.5, 7.5 cm H2O/L/sec).
• Measurements included maximal power output, respiration rate, minute ventilation, oxygen uptake (VO2), and perceived exertion.

Main Results:

• Maximal power output significantly decreased with higher inspiratory resistance (R7.5).
• Respiration rate and minute ventilation were significantly reduced at higher resistances (R4.5 and R7.5).
• Breathing comfort and breathing effort were significantly impaired with higher resistance, while VO2 and rating of perceived exertion remained unchanged.

Conclusions:

• Increased inspiratory resistance negatively affects maximal exercise capacity and breathing perception in hypoxia.
• Low-to-moderate inspiratory resistance does not significantly impair VO2 or overall perceived exertion during exercise.
• Manufacturers and users should consider the perceptual and physiological effects of respirator inspiratory resistance during selection and design.